1. Field of the Invention
The present invention relates to a method of manufacturing a liquid injection head and an exposure method.
2. Description of the Related Art
A recording apparatus (ink jet recording apparatus) using an ink jet system is adapted to perform recording by ejecting an ink (recording liquid) droplet from an ejection orifice of a nozzle of a liquid injection head and adhering the ink droplet to a recording medium.
An exemplary structure of the liquid injection head is described in the following. In the liquid injection head, multiple nozzles are provided on a silicon substrate. Electric wiring and ejection energy generating elements for generating energy for ejecting ink are provided on a surface of the silicon substrate. Each of the nozzles includes an ink flow path (liquid flow path) which itself includes a bubble generating chamber for generating a bubble using the ejection energy generating element and a minute ejection orifice for ejecting a liquid droplet. Further, the silicon substrate has an ink supply port provided therein for supplying ink to the ink flow paths, the ink supply port communicating with a front surface and a rear surface of the silicon substrate.
In a liquid injection head having such a structure, ink supplied from the rear surface of the silicon substrate is supplied through the ink supply port to the respective ink flow paths to fill the bubble generating chambers. Ink which fills the bubble generating chamber is ejected in a direction substantially orthogonal to the silicon substrate by a bubble generated by the ejection energy generating element.
Japanese Patent Application Laid-Open No. H07-171956 discloses a recording head formed by linearly connecting two recording heads. In a recording head formed by linearly connecting two recording heads, the dot density on a sheet corresponding to a head connecting portion in which the density of the ejection orifices is low becomes lower than that in other portions on the sheet. Therefore, in Japanese Patent Application Laid-Open No. H07-171956, the ink ejection direction is inclined toward the connecting portion so that the dot density at the connecting portion and the dot density in other portions are the same. In order to incline the ejection direction, the ejection orifices are formed into an inclined shape. Further, Japanese Patent Application Laid-Open No. H07-171956 describes two methods of manufacturing ejection orifices which are inclined at a fixed angle. In the first method, after a thick film resist is applied to a Ni plate, the film resist is subject to oblique exposure to form nozzle cylinders, and then, Ni plating is applied to the nozzle cylinders to manufacture an orifice plate. In the second method, after photosensitive glass is applied, the glass is subject to oblique exposure to manufacture an orifice plate.